Cutting guide with integral clamping and alignment

ABSTRACT

A portable guide for use with portable power tools such as saws and routers to assist in making straight cuts or grooves precisely located in panels or sheets by moving the tool along a planar side surface  64  of a guide bar  10.  Clamp assemblies  20 R and  20 L secure the guide bar  10  to the workpiece and support the workpiece by clamping the workpiece on both sides of the line of cut via a tightening clamp screw  26  and planar clamp plate  28  that forcefully urge the workpiece into contact with an angle portion  66  of the frame  21  of the clamp assemblies  20 R and  20 L. The clamp assemblies  20 R and  20 L are designed to avoid interference between the clamp assemblies and the cutter portion of the power tool. A template  40  precisely locates the clamp assemblies relative to the line of cut. A lateral guide  30  may be attached to the tool without tool modification. The lateral guide  30  interacts slidably with the guide bar  10  and maintains engagement between the side surface  64  of the guide bar  10  and the power tool.

[0001] This is a Continuation application of prior application No. thatwas filed on

BACKGROUND-FIELD OF INVENTION

[0002] This invention relates to portable cutting guides, specificallyguides used to accurately locate cuts or grooves made in flat panelswith portable cutting or routing tools.

BACKGROUND-DISCUSSION OF PRIOR ART

[0003] Guide devices for portable tools, such as routers or circularsaws, are the subject of extensive prior art. Guides are essential tosuccessful cutting or grooving of sheet materials, such as plywood. Manydevices have been developed to guide portable tools in these operations.The most successful of these are stationary devices, commonly known aspanel saws. These provide a rigid supporting frame for the panel beingcut or grooved and a sliding support to which the tool is attached thatcan be aligned with the desired line of cut. Panel saws are not relevantprior art for the subject invention, which is portable and can beproduced at low cost.

[0004] The extensive prior art in portable devices has significantshortcomings. These shortcomings include:

[0005] A. lack of convenient and economical means of preventing the sawbase plate from moving away from or underneath the guide.

[0006] B. lack of an adequate and convenient means of clamping the guideto the workpiece.

[0007] C. lack of convenient, durable, and universal means of settingthe guide bar position relative to the line of cut for cutsperpendicular or diagonal to the edge of the workpiece.

[0008] In addition, the most common commercial manifestations of theprior art are not suitable for sustained professional use because of lowstrength and durability. In this discussion we have referred primarilyto applications for cutting or sawing operations. It is understood thatsome of the prior art is also applicable to guiding router operation,and that these comments apply as well to such use.

SUMMARY OF PRIOR ART

[0009] Each example of prior art can be described according to how itaddresses three fundamental requirements. These requirements correspondto the shortcomings noted as A, B, and C in the previous paragraph.

[0010] Requirement A: The guide must provide lateral support to preventthe saw from moving away from the intended line of cut

[0011] Requirement B: The guide must be secured relative to theworkpiece during the cutting operation.

[0012] Requirement C: The guide must be aligned so that the saw cut isin the intended location even though the edge of the tool base plate isinvariably offset from the blade or cutter.

[0013] To clarify the discussion of the prior art we have categorizedrepresentative devices according to the approach taken toward meetingeach of these requirements. The approach taken to requirement A definesthe lateral support system. The approach taken to requirement B definesthe clamping system. The approach taken to requirement C defines thealignment system.

[0014] Lateral Support System

[0015] Each example of prior art uses one of four types of lateralsupport: 1) guide bar or straight edge only, 2) tool base attachment ormodification, 3) saw supported on guide bar or bar extension, and 4)frame-type.

[0016] The straight edge only type of device simply provides a rigidguiding edge along which the base plate of the saw is manually heldduring cutting. This type of device is the most economical but fails toprovide adequate lateral guidance, That is, the saw can drift away fromthe guiding edge or, if the material being cut is flexible, the baseplate of the saw can slip under the guiding edge. U.S. Pat. No.4,381,103 to Ferdinand, et al, (1983) describes a device of this type.U.S. Pat. No. 5,138,759 to Gruetzmacher (1992) also describes a deviceof this type. In both cases, the focus of the patent is on a novel meansof connecting two shorter guides to create one long guide. A widelydistributed commercial version of each of these devices is nowavailable. While differing in design details, the patents listed inTable 1 all describe devices that are of the straight edge only type.The patent descriptions for these devices do not specify any means toprevent lateral movement of the saw other than contact on one side ofthe saw base plate. TABLE 1 Patents Covering Straight-Edge Only DevicesPatent Inventor Date Granted 3,085,343 Harold O. Skripsky Apr. 16, 19633,874,261 Gerald A. Murray Apr. 1, 1975 3,910,146 William L. Earl Oct.7, 1975 4,031,974 Joseph Q. Leihgeber Jun. 28, 1977 4,054,077 ReginaldH. Gram Oct. 18, 1977 4,065,114 Charles A. Pennington Dec. 27, 19774,179,965 F. Walter Johnson Dec. 25, 1979 4,736,523 James Hanning Apr.12, 1988 4,843,728 John G. R. Francis Jul. 4, 1989 4,056,028 G. KeithPatterson Nov. 1, 1977 4,306,479 James F. Eberhardt Dec. 22, 19814,381,103 Irwin J. Ferdinand, et al Apr. 26, 1983 4,463,644 Irwin J.Ferdinand, et al Aug. 7, 1984 5,138,759 Richard J. Gruetzmacher Aug. 18,1992 5,148,730 Ronald A. McCaw Sept. 22, 1992 5,226,345 Timothy GambleJul. 13, 1993 5,472,029 Andrew D. Ketch Dec. 5, 1995

[0017] The second lateral support system incorporates an attachment ormodification to the saw base plate. These attachments include bolt-on orclamp-on extensions to the saw base as well as novel saw base designs,requiring changes in the manufacture of the saw. These base platemodifications are intended to improve guidance of the saw by interactingwith the saw guide bar to prevent lateral movement The attachments orbase plate modifications include hooks, glides, bearings, or otherdevices that slidably interface with the guide bar. The disadvantages ofthese devices are 1) they add complexity and cost to the cutting guidesystem, 2) they complicate use of the cutting guide by requiringattachment and alignment of a device not anticipated by the sawmanufacturer, 3) they introduce a potential safety hazard if improperlysecured or aligned, 4) they reduce the portability and flexibility ofthe saw to which they are attached, and 5) the attachments may not beappropriate for all saws given the variety of designs and materials usednow for saw base plates. As noted, some of the prior art recommendsmodifications that would have to be incorporated during saw manufacture,making retrofit very inconvenient. Patents listed in Table 2 describedevices that utilize base plate modifications or attachments. TABLE 2Patents Covering Devices Requiring Base Plate Attachments orModifications Patent Inventor Date Granted 2,677,399 Floyd R. GetsingerMay 4, 1954 2,708,465 Floyd C. Huebner May 17, 1955 2,942,633 Berton E.King Jun. 28, 1960 2,773,523 Lloyd M. Hopla Dec. 11, 1956 3,586,077Mason E. Pease Jun. 22, 1971 3,389,724 Bryant M. Paul Jun. 25, 19683,536,112 Steve Kordyban Oct. 27, 1970 3,829,231 Thomas Hamilton Aug.13, 1974 3,869,951 William J. Litwin Mar. 11, 1975 3,979,987 T. H.Mayhew, M. G. Rice Sept. 14, 1976 4,077,292 Eugene E. Cole Mar. 7, 19784,202,233 Keith J. Larson May 13, 1980 4,777,726 Randy Flowers Oct. 18,1988 4,919,384 Gerhard Grimberg Apr. 24, 1990 4,059,038 Simon P. ReitemaNov. 22, 1977 4,291,602 John Fast, Harvey Williams Sept. 29, 19814,335,512 Martin I. Sheps, et al Jun. 22, 1982 4,619,170 Peter MaierOct. 28, 1986 4,677,750 Peter Maier, Gernot Hansel Jul. 7, 19875,084,977 Robert E. Perkins Feb. 4, 1992

[0018] The third category of lateral support uses a lateral extension ofthe guide bar to provide a surface that supports the saw along theentire path of the cut. In essence, the saw rests on a surface of theguide bar during the cut rather than on the workpiece. The actualguiding edge is attached to this surface or is an integral part of thesurface formed by a raised edge. This approach prevents the saw baseplate from sliding under the guiding edge, since that edge is securedalong its length to the supporting plate. However, movement away fromthe guiding edge is still a potential problem. Some devices in thiscategory improve the lateral support by adding base plate attachments ormodifications that slidably attach to the guiding edge. Several devicesessentially cradle the saw in a channel to prevent lateral movement. Thedisadvantages of devices that support the saw on the guide bar or on anextension of the guide bar include additional cost and complexity,particularly for devices incorporating attachments to the saw base.Patents that define devices supporting the base of the saw along theline of cut are listed in Table 3. TABLE 3 Devices Supporting the Saw onthe Guide Bar or Extension Patent Inventor Date Granted 2,677,399 FloydR. Getsinger May 4, 1954 2,708,465 Floyd C. Huebner May 17, 19553,389,724 Bryant M. Paul Jun. 25, 1968 3,536,112 Steve Kordyban Oct. 27,1970 3,830,130 Harold E. Moore Aug. 20, 1974 3,869,951 William J. LitwinMar. 11, 1975 3,983,776 Robert D. Flanders Oct. 5, 1976 4,050,340 RobertD. Flanders Sept. 27, 1977 4,075,920 Edwin S. Neal Feb. 28, 19784,919,384 Gerhard Grimberg Apr. 24, 1990 4,059,038 Simon P. Reitema Nov.22, 1977 4,224,855 Emile A. Des Roches Sept. 30, 1980 4,244,118 ChesterMatuszak Jan. 13, 1981 4,291,602 John Fast, Harvey Williams Sept. 29,1981 4,307,513 Charles A. Genge Dec. 29, 1981 4,356,748 Charles W.Tilton Nov. 2, 1982 4,453,438 Joseph M. Zelli Jun. 12, 1984 4,539,881Peter Maier Sept. 10, 1985 4,619,170 Peter Maier Oct. 28, 1986 4,811,643George A. Krieger Mar. 14, 1989 4,867,425 Humbert G. Miraglia, Jr. Sept.19, 1989 5,182,975 John L. Warner Feb. 2, 1993 5,206,999 Tom Stone May4, 1993 5,365,822 Michael F. Stapleton Nov. 22, 1994 5,427,006 JoeFinley Jun. 27, 1995

[0019] The fourth lateral support category adds further complexity byproviding a rigid frame which mounts to a bench or work table. The framehas a plate member to which the saw can be attached and which can slidealong the cut axis. The workpiece is generally supported by the benchunder the frame and cut by sliding the saw along a rail fixed to theframe. These devices are similar to panel saws, but are more portableand less expensive. Still, relative to the other portable guide typesthey are quite expensive. In addition, they are complicated to use,requiring securing the saw to the guide plate and rail. This reduces theflexibility of the portable saw. Frame-type devices also restrictflexibility in that the workpiece must be positioned beneath thesupporting frame. This limits the angles of cut possible for a largeworkpiece. Patents describing devices of this type are listed in Table4. TABLE 4 Patents Describing Frame-Type Devices Patent Inventor DateGranted 2,735,456 James W. W. Grier Feb. 21, 1956 Verlee P. Grier4,023,273 Thomas R. Treleaven May 17, 1977 4,125,942 Ralph J. HornerNov. 21, 1978 4,995,280 Michael Della Polla Feb. 26, 1991 4,947,910Raymond P. Reneau Aug. 14, 1990 5,427,006 Joe Finley Jun. 27, 19955,394,781 Ryozo Tsubai Mar. 7, 1995

[0020] Clamping Systems

[0021] Devices covered by prior art do not provide for adequate clampingof the guide bar to the workpiece so that it is secure throughout thecutting process. Much of the prior art provides no integral clampingmethod, relying on the user to provide a clamping system or on frictionto secure the guide to the workpiece. Where a clamping system ismentioned in the prior art, it provides clamping on only one side of theline of cut This can result in sagging of the workpiece during thecutting or grooving process, allowing the edges of the cut to bind onthe cutter and permitting premature separation of the workpiece near theend of the cut This results in breakage of the workpiece. In addition,this lack of support can create a safety hazard. As the materialseparates at the end of the cut it will fall if not adequatelysupported. This subjects the saw operator to risk of injury and theworkpiece to damage. Using the prior art, avoiding these problemsrequires elaborate and time-consuming creation of special supports underthe workpiece or assistance from a helper, who holds the workpiece atthe end of the cut. None of the prior art incorporates a clamping systemwhich adequately secures the work by providing clamping on both sides ofthe line of cut, thereby fixing the relative position of the twosections of the workpiece created by the cutting process.

[0022] Prior art uses one of five types of clamping systems. In a fewinstances, more than one type of clamping system is employed for a givendevice. To some extent, the clamping system is a reflection of thelateral support category, as these are defined above. The clampingsystems evident in the prior art are 1) hand held, 2) user-supplied orindependent clamps, 3) integral clamps on one side of the cut, 4) nailsor screws, and 5) bottom and top rails that sandwich the workpiece.

[0023] Hand held devices are generally intended for smaller guides usedfor cut-off operations on dimensioned lumber, for example U.S. Pat. No.3,869,951 by Litwin (1975). However, some larger devices are describedas hand held employing high friction materials to assist in fixing theguide against the workpiece, for example U.S. Pat. No. 4,811,643 byKlieger (1989). The disadvantages of a hand held device for all but veryshort cuts are that it is difficult to keep the guide in position and itleaves the operator with only one free hand. Typical human arm lengthobviously limits the length of cut. Safety concerns of hand held devicesare a further disadvantage, especially since the workpiece against whichthe device is held is being severed by the saw. Frame-type devices are aspecial case of hand held devices, in which the device is fixed to abench and the workpiece is hand held in cutting position. Patentsdescribing hand held devices are listed in Table 5. TABLE 5 PatentsDescribing Devices With no Mechanical Clamping System (Hand Held) PatentInventor Date Granted 2,735,456 J. W. W. Grier, V. P. Grier Feb. 21,1956 3,536,112 Steve Kordyban Oct. 27, 1970 3,869,951 William V. LitwinMar. 11, 1975 3,979,987 T. H. Mayhew, M. G. Rice Sept. 14, 19764,028,976 Peter Kundikoff Jun. 14, 1977 4,054,077 Reginald H. Gram Oct.18, 1977 4,125,942 Ralph J. Horner Nov. 21, 1978 4,736,523 James HanningApr. 12, 1988 4,777,726 Randy Flowers Oct. 18, 1988 4,843,728 John G. R.Francis Jul. 4, 1989 4,995,288 Michael Della Polla Feb. 26, 19915,271,159 Andy H. T. Chen Dec. 21, 1993 4,056,028 G. Keith PattersonNov. 1, 1977 4,306,479 James F. Eberhardt Dec. 22, 1981 4,335,512 MartinI. Sheps, et al Jun. 22, 1982 4,494,434 Robert W. Young Jan. 22, 19854,539,881 Peter Maier Sept. 10, 1985 4,619,170 Peter Maier Oct. 28, 19864,677,750 Peter Maier, Gernot Hansel Jul. 7, 1987 4,811,643 George A.Krieger Mar. 14, 1989 4,947,910 Raymond P. Reneau Aug. 14, 19905,084,977 Robert E. Perkins Feb. 4, 1992 5,226,345 Timothy Gamble Jul.13, 1993 5,427,006 Joe Finley Jun. 27, 1995 5,394,781 Ryozo Tsubai Mar.7, 1995

[0024] Devices that rely on the user to supply clamps or on clamps whichare not an integral element of the guide design more effectively securethe guide to the workpiece. However, These can be awkward to use as itgenerally takes a firm hand to hold the guide bar in place leaving onlyone hand to set and secure the clamps. An additional challenge ariseswhen protecting the workpiece requires the use of pads over the clampjaws. These must be held in place while setting the clamps. Typically,one clamp is needed at each end of a cut. On longer cuts it is difficultto get both ends of the guide clamped in proper position in one try.Normally, the clamps and guide bar require readjustment after initialclamping. Patents describing devices that require user supplied orindependent clamps are listed in Table 6. TABLE 6 Patents DescribingDevices with Independent or User-Supplied Clamping Patent Inventor DateGranted 2,677,399 Floyd R. Getsinger May 4, 1954 2,773,523 Lloyd M.Hopla Dec. 11, 1956 3,536,112 Steve Kordyban Oct. 27, 1970 3,830,130Harold E. Moore Aug. 20, 1974 3,983,776 Robert D. Flanders Oct. 5, 19764,077,292 Eugene E. Cole Mar. 7, 1978 4,125,942 Ralph J. Horner Nov. 21,1978 4,059,038 Simon P. Reitema Nov. 22, 1977 4,307,513 Charles A. GengeDec. 29, 1981 4,453,438 Joseph M. Zelli Jun. 12, 1984 4,677,750 PeterMaier, Gernot Hansel Jul. 7, 1987 4,867,425 Humbert G. Miraglia, Jr.Sept. 19, 1989 5,138,759 Richard J. Gruetzmacher Aug. 18, 1992 5,148,730Ronald A. McCaw Sept. 22, 1992 5,206,999 Tom Stone May 4, 1993 5,472,029Andrew D. Ketch Dec. 5, 1995

[0025] An improvement over independent clamps is provided by deviceswith integral clamping. In such devices, the clamps are secured to theguide bar so that they can be conveniently engaged after aligning theguide bar. Some of the prior art suggests extremely complicated andexpensive integral clamping systems, for example U.S. Pat. No. 4,244,118granted to Matuszak (1981) and U.S. Pat. No. 5,427,006 granted to Finley(1995). Two general approaches have been taken. One approach appliesclamping pressure vertically through the plane of the workpiece,pinching the workpiece between the guide bar above and a clamp padbelow. The other approach clamps in the plane of the workpiece like abar clamp extending across the workpiece, for example U.S. Pat. No.4,179,965 granted to Johnson (1979). This type of device is useless onflexible panels, which will simply bend under clamping pressure. Inspite of the advantages of integral clamps over independent clamps,those of the prior art suffer from the same principal drawback that onlyone side of the cut is supported. Patents describing devices withintegral clamping systems are listed in Table 7. TABLE 7 PatentsDescribing Devices with Integral Clamping Patent Inventor Date Granted2,708,465 Floyd C. Huebner May 17, 1955 2,942,633 Berton E. King Jun.28, 1960 2,773,523 Lloyd M. Hopla Dec. 11, 1956 3,085,343 Harold O.Skripsky Apr. 16, 1963 3,586,077 Mason E. Pease Jun. 22, 1971 3,389,724Bryant M. Paul Jun. 25, 1968 3,829,231 Thomas Hamilton Aug. 13, 19743,874,261 Gerald A. Murray Apr. 1, 1975 3,910,146 William L. Earl Oct.7, 1975 4,023,273 Thomas R. Treleaven May 17, 1977 4,031,974 Joseph Q.Leihgeber Jun. 28, 1977 4,050,340 Robert D. Flanders Sept. 27, 19774,065,114 Charles A. Pennington Dec. 27, 1977 4,075,920 Edwin S. NealFeb. 28, 1978 4,179,965 F. Walter Johnson Dec. 25, 1979 4,202,233 KeithJ. Larson May 13, 1980 4,919,384 Gerhard Grimberg Apr. 24, 19904,224,855 Emile A. Des Roches Sept. 30, 1980 4,244,118 Chester MatuszakJan. 13, 1981 4,291,602 John Fast, Harvey Williams Sept. 29, 19814,356,748 Charles W. Tilton Nov. 2, 1982 4,381,103 Irwin J. Ferdinand,et al Apr. 26, 1983 4,463,644 Irwin J. Ferdinand, et al Aug. 7, 19845,365,822 Michael F. Stapleton Nov. 22, 1994

[0026] Several proposed guide devices use nails or screws to secure theguide bar to the workpiece. This approach is clearly tedious and may marthe workpiece. It does have the advantage that it can prevent sagging ofthe center of a flexible workpiece on a long cut. However, if theworkpiece can be supported for nailing to the guide bar, it can besupported during the cut. In general, this is not a practical solutionfor securing a guide to a workpiece. Patents describing devicesincorporating nails or screws as a principal or auxiliary clampingsystem include U.S. Pat. Nos. 3,830,130 by Moore (1971), 4,224,855 byDes Roches (1980), and 4,453,438 by Zelli (1984).

[0027] Some devices use a supporting bar or rail beneath the workpieceand parallel to the guide bar. This essentially clamps or sandwiches theworkpiece between the guide bar and the lower rail. This type of systemprovides excellent support for flexible panels so that the saw baseplate cannot slip under the guide bar. However, it is an expensivesolution that is rather awkward to affix to the workpiece and thatcomplicates supporting the panel to be cut. In addition, like the otherprior art approaches, it does not support the workpiece on both sides ofa cut. Patents describing devices using top and bottom bars to sandwichthe workpiece include U.S. Pat. Nos. 3,389,724 by Paul (1968), 4,075,920by Neal (1978), and 4,291,602 by Fast (1981).

[0028] Alignment Systems

[0029] A third difficulty in using a guide for cutting and routing isthat the cutting blade or tool is offset from the edge of the base plateof the tool. This offset varies according to the specific tool andcutter in use. It is necessary for the guide user to compensate for thisoffset by setting the guide parallel to the line of cut, but removedfrom it by the correct distance. This process introduces errors and istime consuming, particularly since a simple change of blade in a givensaw alters the necessary compensation. Further complication is evidentfor long cuts where the guide must be aligned on both the near and faredges of a cut and then secured to the workpiece. Adjustment of theguide on one edge cannot be made without disturbing the position at theother edge, at least not with any of the prior art devices. Alignmentsystems in the guides of prior art fall into one of six categories. 1)user measures the offset required, 2) a rod or tab extends from theguide bar or edge clamp and is calibrated by a saw cut, 3) the guide barhas a lateral extension over its entire length that is calibrated by aninitial saw cut, 4) the edge stop or clamp is marked by a saw cut, 5) anoffset gauge is positioned against the guide bar and aligned with theintended line of cut, and 6) the workpiece is moved to position underthe saw, which is fixed laterally by a frame.

[0030] Devices in the first category simply rely on the user to measurethe offset for a particular saw and set the guide that distance from theintended line of cut. This approach has the obvious disadvantages ofinconvenience and risk of error in making the several measurementsrequired to set the guide position on both edges of a workpiece. Patentsdescribing devices for which no alignment means is specified are listedin Table 8. TABLE 8 Patents Describing Devices with no Alignment SystemSpecified Patent Inventor Date Granted 2,677,399 Floyd R. Getsinger May4, 1954 2,708,465 Floyd C. Huebner May 17, 1955 3,085,343 Harold O.Skripsky Apr. 16, 1963 3,586,077 Mason E. Pease Jun. 22, 1971 3,389,724Bryant M. Paul Jun. 25, 1968 3,829,231 Thomas Hamilton Aug. 13, 19743,869,951 William J. Litwin Mar. 11, 1975 3,874,261 Gerald A. MurrayApr. 1, 1975 3,979,987 T. H. Mayhew, M. G. Rice Sept. 14, 1976 3,983,776Robert D. Flanders Oct. 5, 1976 4,023,273 Thomas R. Treleaven May 17,1977 4,031,974 Joseph Q. Leihgeber Jun. 28, 1977 4,050,340 Robert D.Flanders Sept. 27, 1977 4,077,292 Eugene E. Cole Mar. 7, 1978 4,125,942Ralph J. Horner Nov. 21, 1978 4,179,965 F. Walter Johnson Dec. 25, 19794,202,233 Keith J. Larson May 13, 1980 4,736,523 James Hanning Apr. 12,1988 4,777,726 Randy Flowers Oct. 18, 1988 4,919,384 Gerhard GrimbergApr. 24, 1990 4,995,288 Michael Della Polla Feb. 26, 1991 4,224,855Emile A. Des Roches Sept. 30, 1980 4,335,512 Martin I. Sheps, et al Jun.22, 1982 4,381,103 Irwin J. Ferdinand, et al Apr. 26, 1983 4,463,644Irwin J. Ferdinand, et al Aug. 7, 1984 4,619,170 Peter Maier Oct. 28,1986 4,677,750 Peter Maier, Gernot Hansel Jul. 7, 1987 4,947,910 RaymondP. Reneau Aug. 14, 1990 5,084,977 Robert E. Perkins Feb. 4, 19925,138,759 Richard J. Gruetzmacher Aug. 18, 1992 5,394,781 Ryozo TsubaiMar. 7, 1995 5,427,006 Joe Finley Jun. 27, 1995

[0031] A common system to avoid the need for manually setting the guidebar position is to provide for a rod or tab to be inserted into areceiver in the guide bar. This rod or tab is made of wood or othermaterial that can be cut with the saw. Then, when the saw is firstpassed along the guide bar, the extending rod or tab will be cut at adistance from the guide bar precisely equal to the correct offset. Forsubsequent cuts using the same saw and blade, the guide bar ispositioned by aligning the cut edge of the rod or tab with the intendedline of cut. If the rod or tab is secured to the guide bar, then it canbe used for cuts diagonal to the edge of the workpiece as well as forperpendicular cuts. A disadvantage of this approach is that the rod ortab must be removed from the guide bar during the cut so that it doesnot interfere with the saw's path along the guide bar. Some rathercomplicated schemes have been devised to implement this simple concept.This translates into high cost and inconvenience. Another difficulty isthat a rod or tab at the end of a guide bar is useless for setting thebar for shorter cuts where the guide bar extends beyond the workpiece.To overcome this difficulty, movable tabs have been proposed. Thisfurther complicates construction of the guide bar. An alternative is toinsert the measuring tab or rod into the end clamp of the guide bar.This applies only for cutting guides that have integral clampingsystems. With this approach, the rod or tab can be used on any widthworkpiece. Unfortunately, a given rod or tab is only useful for oneparticular angle of cut if it is fixed to the end clamps. Finally, allof these devices have the aforementioned shortcoming that setting theguide on one edge of a workpiece will typically change the position ofthe guide at the other edge, requiring an iterative process to obtain anaccurate setting. It would be preferable if alignment at one edge wereindependent of alignment at the other edge. Patents describing devicesthat employ a rod or tab calibrated by a saw cut as an alignment aid arelisted in Table 9. TABLE 9 Patents Describing Devices Using a Rod or TabExtending from the Guide Bar for Alignment Patent Inventor Date Granted4,028,976 Peter Kundikoff Jun. 14, 1977 4,843,728 John G. R. FrancisJul. 4, 1989 4,056,028 G. Keith Patterson Nov. 1, 1977 4,291,602 JohnFast, Harvey Williams Sept. 29, 1981 4,811,643 George A. Krieger Mar.14, 1989 5,226,345 Timothy Gamble Jul. 13, 1993

[0032] The third system found in the prior art is commonly used forguides that include a broad base upon which the saw slides during thecut. This base can be made of a cutable material, such as fiberboard.When a given saw is first used on this type of guide, the resulting cutedge has the proper offset from the raised guide edge along which thesaw base plate moves. The guide is then aligned for subsequent cuts byplacing this cut edge against the intended line of cut. This approachcan be used for diagonal or perpendicular cuts at 90 degrees to theplane of the workpiece surface. For bevel cuts (those not perpendicularto the surface), the offset changes and the calibration is no longervalid. The calibration is only valid for a given saw and blade in anycase, so that a new guide (or at least a new guide extension) isrequired to accommodate a change of blade. U.S. Pat. No. 5,365,822 byStapleton (1994) describes a guide where the base on which the aligningedge is cut is an integral extension to the guide bar. Each saw andblade combination, therefore, requires a separate device. A morepractical approach is reflected in U.S. Pat. No. 4,867,425 by Miraglia(1989), which mounts a guiding edge onto a disposable panel offiberboard or similar material that is then cut to provide the aligningedge. This adds the complication of assembly. A further disadvantage isthat repeated use will feather the edge of the guide making precisealignment more difficult and eventually requiring replacement Patentsdescribing devices that use this type of aligmnent system are listed inTable 10. TABLE 10 Patents Describing Devices that Use a full Length SawCut as an Alignment Aid Patent Inventor Date Granted 3,536,112 SteveKordyban Oct. 27, 1970 3,830,130 Harold E. Moore Aug. 20, 1974 4,075,920Edwin S. Neal Feb. 28, 1978 4,059,038 Simon P. Reitema Nov. 22, 19774,244,118 Chester Matuszak Jan. 13, 1981 4,307,513 Charles A. Genge Dec.29, 1981 4,356,748 Charles W. Tilton Nov. 2, 1982 4,453,438 Joseph M.Zelli Jun. 12, 1984 4,539,881 Peter Maier Sept. 10, 1985 4,867,425Humbert G. Miraglia, Jr. Sept. 19, 1989 5,206,999 Tom Stone May 4, 19935,365,822 Michael F. Stapleton Nov. 22, 1994

[0033] The fourth alignment system also uses an initial saw cut forcalibration. However, the cut is made in the end block or clampingsystem that abuts the edge of the workpiece. The end block simplyextends beyond the edge of the guide bar sufficiently so that when thesaw is passed along the guide bar it makes a cut in the end block Thiscut is then aligned on the edge of a workpiece at the intended line ofcut. This approach has the disadvantage that the initial cut is onlyappropriate for one angle of cut and one bevel angle. Cuts at severalangles will quickly destroy the end block, requiring replacement of thisintegral part of the panel cutting guide. Patents employing saw cuts onan end block to calibrate the alignment system include U.S. Pat. Nos.4,054,077 to Gram (1977), 4,065,114 to Pennington (1977), and 4,306,479to Eberhardt (1981).

[0034] The fifth type of alignment system is the offset gauge. Thisgauge is simply a spacer of width precisely equal to the necessaryoffset. A series of gauges or a gauge with several dimensions can beused for various saw and blade combinations. A variation on the offsetgauge approach uses an alignment bar attached via hinge to the guidebar. An example of this variation is U.S. Pat. No. 5,472,029 to Ketch,Dec. 5, 1995. This device includes a gauge bar parallel to the guide barthat can be set at the correct distance for each tool and cutter. It isconnected to the guide bar by a hinge and can be swung out of the wayafter using it to position the guide bar. This approach should be easierto use for aligning both ends of the guide bar because the gauge bar isquite long. However, it has other shortcomings, Aside from the obviousexpense of such a device, it is apparent that setting and resetting itwith a change of tools or cutters is an awkward task. It is possible tocalibrate the offset gauge with a saw cut for some proposed designs. Theoffset gauge can be used for angle cuts, will not wear appreciably inuse, and can be inexpensively replaced for some designs. However, it isawkward to use in that it is one more item to handle while aligning andclamping opposite ends of a guide bar along a cut. Patents describingdevices using offset gauges are listed in Table 11. TABLE 11 PatentsDescribing Devices that Use an Offset Gauge for Alignment PatentInventor Date Granted 2,942,633 Berton E. King Jun. 28, 1960 2,773,523Lloyd M. Hopla Dec. 11, 1956 3,910,146 William L. Earl Oct. 7, 19754,028,976 Peter Kundikoff Jun. 14, 1977 5,271,159 Andy H. T. Chen Dec.21, 1993 4,356,748 Charles W. Tilton Nov. 2, 1982 4,494,434 Robert W.Young Jan. 22, 1985 5,148,730 Ronald A. McCaw Sept. 22, 1992 5,472,029Andrew D. Ketch Dec. 5, 1995

[0035] The sixth alignment system in prior art is applicable toframe-type devices only. For such devices the frame supporting the sawis fixed above a work surface and the workpiece is simply slid intoposition beneath the saw. The saw blade can generally be visuallyaligned with the intended line of cut. This system is not relevant tothe portable guide system anticipated in this patent application

OBJECTS AND ADVANTAGES

[0036] The cutting guide of the current invention addresses theshortcomings of prior art as described below, providing an economicalguide system with previously unknown safety and convenience. It providessignificant advantages for each of the basic requirements of a cuttingguide:

[0037] (a) the invention provides lateral support to prevent movementaway from the line of cut without the use of saw base modifications orcomplicated base plate attachments;

[0038] (b) the invention provides integral means of securing the guideto the workpiece with clamps that secure the workpiece on both sides ofthe cut so that the workpiece will not collapse during or after the cut;

[0039] (c) the invention provides an easily used alignment system thatis universal in that it can be used for any angle of cut and any saw andblade combination;

[0040] (d) the alignment system assures that alignment at one edge ofthe workpiece does not disturb the alignment at the other edge.

[0041] (e) the invention provides for an economical device because thecomplications evident in some prior art are avoided;

[0042] (f) the invention provides for increased safety and productivitybecause of the ease of use and inherent advantages of the clamping andalignment systems.

[0043] Further objects and advantages of my invention will becomeapparent from a consideration of the drawings and ensuing description.

DESCRIPTION OF DRAWINGS

[0044] The invention in a preferred embodiment is represented in FIGS.1, through 8 b.

[0045]FIG. 1 is an isometric overview of the invention as it might lookin practice attached to a panel to be cut.

[0046]FIG. 2a is a partially exploded isometric overview without thepanel in place showing the guide bar separated from the clamp bars forclarity.

[0047]FIG. 2b shows the underneath side of the guide bar.

[0048]FIG. 3 shows the left and right hand clamp bars fully assembled.

[0049]FIG. 4 is an exploded isometric view of the right hand clamp bar.

[0050]FIGS. 5a, 5 b, and 5 c are a partial elevation view of a clamp barshowing the means of tensioning the T-bolt that attaches the-guide barto the clamp bars.

[0051]FIGS. 6a, 6 b, and 6 c show an alternative means of tensioning theT-bolt.

[0052]FIG. 7 shows the template used to align the guide.

[0053]FIG. 8a shows the a lateral guide suitable for use with a circularsaw attached to such a saw.

[0054]FIG. 8b shows a variation on the lateral guide. List of ReferenceNumerals 10 guide bar 11 guide bar slots 20L left hand clamp barassembly 20R right hand clamp bar assembly 21 clamp bar frame 22 T-bolt24 eccentric lever 25 pin 26 clamp screw 27 clamp nut 28 clamp plate 29handle 40 template 50 threaded T-bolt 51 tensioning wedge 52 taperedwasher 53 threaded nut 60 protection wall 61 lower wall 62 frame notch63 work piece engagement wall 64 guide bar side surface 65 angled edge66 frame angle portion

SUMMARY

[0055] A cutting guide as disclosed by the present invention comprises aguide bar that restricts the lateral movement of a cutting tool, twoclamp bars that secure the guide bar to the workpiece, a means ofpositioning the clamp bars relative to the intended line of cut, a meansof attaching the guide bar to the clamp bars, and a fence accessoryfixture for the cutting tool to aid in following the guide bar.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0056] A convenient embodiment of the cutting guide of the presentinvention is illustrated in FIG. 1 as it may appear in use. The cuttingguide is comprised of a guide bar 10 of rigid material and of uniformcross section such that it presents a straight edge along which thecutting tool, shown here as a circular saw, can advance. The guide baris secured to the workpiece in the proper position relative to theintended line of cut by attachment to two clamp bars 20R and 20L, one ateither end of the cut. The clamp bars are secured to the work piece byintegral clamps. The clamp bars are notched or otherwise designed toavoid interference with the cutter. The cutting guide may be used with afence 30, that attaches to the saw or tool base plate and hooks over theguide bar, restricting lateral movement of the tool away from or beneaththe guide bar. A template 40 that is used for alignment is shown lyingon the workpiece in FIG. 1. An exploded overview is shown in FIG. 2without the workpiece in place to more clearly show the main components.

[0057] The guide bar 10 comprises a rigid tube having a plurality ofplanar surfaces, including a side surface 64 that engages a portion ofthe cutting tool, that provide a rectangular cross section with slots 11in the bottom surface centered along the longitudinal axis as shown inFIG. 2b. To maintain the strength of the guide bar, a series of slotsmay be used rather than one continuous slot. The width of the slots isequal to the width of the T-bolt 22 so that the T-bolt can be insertedinto the slot 11 when it is turned with the long axis to the T-bolt headaligned with the axis of the slot. When turned at 90 degrees to thisorientation, the edges of the T-bolt head will engage the edges of theslot. This is shown in detail in FIGS. 5a, 5 b, and 5 c.

[0058] The clamp bars, 20R shown also in exploded view in FIG. 4 and20L, serve the dual purpose of attaching the cutting guide to theworkpiece and of holding the workpiece together during and after thecutting operation. There is one left hand 20L and one right hand 20Rclamp bar required. Each clamp bar consists of a rigid frame 21 thatholds two clamps for attaching the clamp bar to the workpiece and aT-bolt system for securing the clamp bars to the guide bar 10. The leftand right hand clamp bars differ by including the T-bolt system onopposite sides of the centerline of the frame 21. The clamps in thepreferred embodiment each consist of a clamp screw 26 with handle 29, anut 27 affixed to the frame 21, and a clamp plate 28 riveted to the topof the clamp screw 26.

[0059] Referring to FIGS. 3 and 4, the frames 21 of the clamp assemblies20R and 20L further include a protection wall 60 that perpendicularlyjoins with a lower wall 61, and angle portions 66 that perpendicularlyjoin with a workpiece engagement wall 63 which includes a frame notch62. The protection wall 60 prevents the workpiece from engaging theclamp nuts 27 affixed to the lower wall 61, and the clamp plates 28riveted to a top portion of the clamp screws 26, when the workpiece isinserted in the space between the protection wall 60 and the angleportions 66 to ultimately contact the engagement wall 63. The angleportions 66 cooperate with the frame notch 62 and the clamp plates 28 tomaintain the positions of two separated distinct portions of theoriginal workpiece, when a saw blade or comparable power tool passesthrough the frame notches 62 of both clamp assemblies 20R and 20L. Theangle portions 66 have a lateral dimension substantially equal to thelateral dimension of the lower wall 61; however, both the lateral andlongitudinal dimensions of the angle portions 66 may be increased toprovide an increased surface area sufficient to support relatively largeand/or heavy separated portions of the original workpiece.

[0060] The angle portions include inner angled edges 65 that converge asthe angled edges 65 approach the engagement wall 63. The angled edges 65provide a visual aid to the power tool operator to help avoid contactbetween the saw blade and the angle portions 66 as the power tool nearsthe frame notch 62 in the clamp assemblies 20R and 20L during thecutting operation. The frame notch 62 allows a saw blade to pass throughthe frame 21 thereby avoiding engagement between the saw blade and theclamp assemblies 20R and 20L while the saw blade continues cutting theworkpiece beyond the perimeter defined by the engagement walls 63 of theclamp assemblies 20R and 20L.

[0061] The T-bolt system for attaching the guide bar 10 consists of theT-bolt 22, which fits into the T-bolt channel 23 and a means oftensioning the T-bolt when it is inserted into slots in the guide bar10. A tensioning system is shown in FIGS. 5a, 5 b, and 5 c. An eccentriclever or cam is affixed to the T-bolt by means of a pin 25, which islocated off-center at the round end of the lever 24. Flipping theeccentric lever from one side to the other will raise and lower theT-bolt 22. This motion is used to secure the clamp bars 20R and 20L tothe guide bar 10. FIGS. 6a through 6 c show an alternative tensioningsystem using wedge 51 positioned on a threaded T-bolt 50 with a matchingtapered washer 52 and threaded nut 53. The threaded T-bolt 50 isflattened on two opposite sides so that the wedge 51 and tapered washerwill maintain the correct relative positions. The flats also permitrotation of the T-bolt by rotation of the wedge, which is required foroperation as described below. FIG. 7 shows a template 40, which is usedto position the clamp bars. The template is made of thin durablematerial that is easy to cut, such as plastic. The template 40 has ahole in one corner that is open on one side forming a notch 41. The holeis of the same diameter as the T-bolt allowing the notch 41 to be usedto position the template against the T-bolt 22 or threaded T-bolt 50.

[0062] The lateral guide 30 shown in FIG. 1 and FIG. 8a conforms to thecross section of the guide bar and extends away from the guide bar forattachment to the tool base. This extended portion is of uniform crosssection appropriate for insertion into the rip fence receiver of thetool. The shaped portion of the lateral guide may be extended in widthto increase the line of contact with the guide bar as shown in FIG. 8b.

OPERATION

[0063] The advantages of the present invention are best clarified by adescription of its operation. A calibration step is required prior tooperation using a given saw so that the template 40 can be used toposition the clamp bars. Once calibrated, the template can be usedrepeatedly for cuts made with the same saw.

[0064] To calibrate the template, a scrap workpiece is placed onconvenient supports, such as saw horses, and the right hand clamp bar20R is fixed to the workpiece along the edge nearest the operator. Thesecond clamp bar 20L is fixed along the opposite edge of the workpiece.The uncalibrated template, shown in FIG. 7, is then placed on the T-boltof the clamp bar 20R by sliding the notch 41 snugly against the T-bolt.The body of the template extends over the line of cut. The template issecured in this position by placing the guide bar 10 in position on theT-bolts of both clamp bars and tensioning the T-bolts as describedbelow. Finally, a light cut taken with the saw will trim the edge of thetemplate, resulting in perfect calibration for the saw and bladecombination. For other saw and blade combinations a separate templatecan be trimmed. Also, one template can have two or more trimmed edges. Atrimmed edge is represented by the dashed line on the template 40 inFIG. 7. It is important for proper use of the template to note that ithas a face and a back side. The side facing upward during thecalibrating cut is the face. The template can be marked or color-codedto clearly indicate the face side.

[0065] Once calibration is completed, accurate positioning and operationof the saw guide is very simple. First, the workpiece is set on suitablesupports, such as saw horses or blocks, positioning the workpieceapproximately horizontal. The intended line of cut is marked eithercompletely across the workpiece or at least near the edges. The righthand clamp bar 20R is placed snugly against the edge where the cut willstart approximately centered on the marked cut line. The calibratedtemplate is positioned against the T-bolt of the clamp bar 20R and theclamp bar is moved left or right along the workpiece edge until thetrimmed edge of the template aligns with the marked line of cut. Thetemplate must be used with the face side up to position the right handclamp bar 20R. Because of the method of trimming the template, the wasteside of the cut is to the left of the line along the edge of thetemplate. This allows for very accurate positioning of the guide. Oncepositioned relative to the line of cut, the clamp bar is secured to theworkpiece by tightening the clamp screws.

[0066] The left hand clamp bar 20L is then positioned in a similarmanner. First, it is placed along the far edge of the workpiece, i.e.,the edge where the cut will be completed. The clamp bar 20L isapproximately centered on the marked line of cut. The template is againused for final positioning of the clamp bar. However, for this left handclamp bar the template must be used with the face side down. Oncepositioned, the clamp screws are tightened. With the clamp bars thuspositioned, it is clear that the line of cut passes through the cut-outin the center of the clamp bars. This allows clearance for the blade tocut through the workpiece without hitting the clamp bar. Note thatsetting the clamp bar on the far edge of the workpiece is completelyindependent of setting the clamp bar on the front edge. No iteration isrequired to attain perfect positioning.

[0067] With the clamp bars 20R and 20L secured, the T-bolts 22 areturned so that the long axis of their rectangular top is parallel to theline of cut. This positioning should also place the tensioning lever 24in a convenient position for its operation. Generally, this will be theloose position with the lever facing away from the workpiece edge. FIGS.5a and 5 b show the loose position for the eccentric tensioner 24. Inaddition, the tensioner 24 is turned so that the top of the T-bolt isaligned with a slot 11 in the guide bar 10. With the T-bolts for boththe left and right hand clamp bars aligned in this way, the guide bar ispositioned over the T-bolts. The tensioner 24 is then rotated about theaxis of the T-bolt so that the top of the T-bolt is alignedperpendicular to the slots 11 in the guide bar as shown in FIG. 5b. Thetensioner 24 is then swung to the tensioned position as shown in FIG.5c, securing the guide bar to the clamp bars.

[0068] An alternative means of tensioning the T-bolt is shown in FIGS.6a through 6 c. With this system, the wedge 51 is pulled out so that theT-bolt is not tensioned. Two opposite sides of the threaded T-bolt 50are machined flat to fit snugly in the slot of the wedge. Therefore, theT-bolt can be rotated by turning the wedge. In addition, the washer 52is slotted to match the cross section of the T-bolt. In this way, thetapered washer will maintain the proper alignment relative to the wedge.Tensioning is accomplished by moving the wedge in the direction of thearrow in FIG. 6b.

[0069] With the guide bar in place, the cut can be completed. The cut ismade from the near edge where the right hand clamp bar is located to thefar edge where the left hand clamp bar is located. The cut is made whileholding the right edge of the saw base against the left side surface 64of the guide bar 10. Note that the workpiece remains supportedthroughout the cut by the clamp bars, which clamp on both sides of thecut. Therefore, it is not necessary to provide independent support forthe workpiece along the line of cut or to have an assistant support thework at the end of the cut.

[0070] The operation is further simplified by use of a lateral guide 30to prevent the saw from drifting away from the edge of the guide bar. Ifthin or flexible material is being cut, there is danger of the saw basesliding under the guide bar as well. The simple lateral guide 30 willprevent both types of lateral movement and can assist in supporting theweight of the saw on flexible workpieces by transferring some of theweight to the guide bar 10. The lateral guide, as shown in FIGS. 1 and8a and 8 b, is attached to the saw in the same manner as the commonlyused circular saw rip fence for making cuts parallel to an existingworkpiece edge. All circular saws are equipped with a receptacle in thebase for such a fence. Thus, no saw modification is required for use ofour lateral guide 30. Other cutting devices, such as jig saws androuters can generally accommodate similar lateral guides.

[0071] After completion of the cut, the T-bolt tension is released andthe guide bar is removed. The clamp bars can then be removed, allowingthe separation of the cut panel.

CONCLUSIONS, RAMIFICATIONS, AND SCOPE OF INVENTION

[0072] Thus it is clear that the cutting guide of the invention offerssignificant advantages in safety, accuracy, simplicity, and economy. Inparticular, it solves the problems of accurate universal alignment,secure support of and to the workpiece, and simple lateral guidance thatare the essential features of a successful guide.

[0073] While the description provided above is specific as to structureand operation, these specifics are not meant as limitations on the scopeof the invention, but as characteristic of one preferred embodiment Manyvariations are possible for each element of the invention. For instance,the clamp assembly may use spring clamps, C-clamps, knuckle clamps orother clamp types. These may be attached by any rigid member constructedso as to avoid interference with the cutting tool, provide the neededstrength to hold the workpiece together, and provide a point ofattachment for the guide bar.

[0074] The guide bar may be constructed of aluminum extrusion with acontinuous slot or other provision for attaching to the clampassemblies. Other materials and designs for the guide bar are alsoacceptable. It may be convenient to provide a slot in the top of theguide bar to receive an edge of the lateral guide rather than have thelateral guide fit over the entire guide bar cross section. Other meansof securing the guide bar to the clamp assemblies can also be used,including bolts, clamps, and various latches, provided that the guidebar can be attached at various angles and in a consistent positionrelative to the clamp assemblies.

[0075] The template can be color coded to indicate the face and reversesides. Corresponding codes may be applied to the left and right handclamp assemblies. The template can be printed with labels or spaces foridentification of the corresponding tools. It can be attached to theclamp assemblies rather than being removable. It may take almost anyplane geometric shape that extends across the line of cut forcalibration.

[0076] Therefore, the scope of the invention should be determined by theappended claims and their legal equivalents rather than by the specificembodiments illustrated in the description and drawings above.

1. A portable guide device for severing a portion of a workpiececomprising: a guide bar having a longitudinal dimension relativelylonger than the preselected portion of the workpiece to be severed; afirst clamp assembly secured to a first end of the workpiece; a secondclamp assembly secured to an opposing second end of the workpiece; meansfor aligning said first and second clamp assemblies; means for securingsaid guide bar to said first and second clamp assemblies; means forcontinuously engaging a severing tool with a longitudinal side surfaceof said guide bar beyond the first and second ends of the workpiece; andmeans for maintaining the relative position of the workpiece and thesevered portion upon completing the severing operation.
 2. The device ofclaim 1 wherein said guide bar further includes a plurality of planarsurfaces that provide a rectangular cross section.
 3. The device ofclaim 1 wherein said guide bar further includes a slot centered alongthe longitudinal axis of a bottom surface of said guide bar.
 4. Thedevice of claim 1 wherein said guide bar further includes a plurality ofslots centered along the longitudinal axis of a bottom surface of saidguide bar.
 5. The device of claim 1 wherein said first and second clampassemblies further include a protection wall to prevent the workpiecefrom engaging nuts affixed to a clamp frame and clamp plates riveted toa top portion of a clamp screw.
 6. The device of claim 1 wherein saidaligning means further includes a template dimensioned to positionT-bolts of said first and second clamp assemblies a predetermineddistance from a line of cut.
 7. The device of claim 6 wherein saidpredetermined distance corresponds to the distance between said T-boltsand the severing tool when said guide bar is secured to said first andsecond clamp assemblies and the severing tool engages a side surface ofsaid guide bar.
 8. The device of claim 6 wherein said template furtherincludes a notch configured to removably and snugly receive saidT-bolts.
 9. The device of claim 1 wherein said guide bar securing meansfurther includes a rectangular top portion of said T-bolts positioned toinsert through said slot in said bottom surface of said guide bar, saidtop portion subsequently being rotated inside said guide bar and urgedinto forcible engagement with an inner portion of said bottom surfacevia an eccentric tensioning lever thereby securing said guide bar tosaid first and second clamp assemblies.
 10. The device of claim 1wherein said guide bar further includes means for securing the severingtool to said guide bar.
 11. The device of claim 10 wherein said severingtool securing means further includes a lateral guide having a firstportion removably positioned upon said guide bar, and a second portionremovably joined to a receptacle portion of the severing tool.
 12. Thedevice of claim 1 wherein said continuous engaging means furtherincludes a notch portion in a frame portion of said first and secondclamp assemblies, said notch portions being substantially centered insaid frame portions, said notch portions being dimensioned to allow thesevering tool to pass through said notches without engaging said firstand second clamp assemblies.
 13. The device of claim 12 wherein saidcontinuous engaging means further includes positioning said longitudinalside surface of said guide bar proximate to said notches to direct thesevering tool through said notches when the severing tool is urgedacross the workpiece while continuously engaging said side surface ofsaid guide bar.
 14. The device of claim 1 wherein said positionmaintaining means further includes opposing clamp screws insertedthrough frame portions of said first and second clamp assemblies oneither side of notch portions in said frame portions, and angle portionsof said frame portions dimensioned to engage corresponding edge portionsof the workpiece when said clamp screws are tightened.
 15. The device ofclaim 1 wherein said guide bar securing means further includes a T-bolthaving a threaded end portion with opposing sides machined flat to fitsnugly in a slot of a wedge and a correspondingly configured washer,said threaded end receiving a nut to secure the relative position ofsaid T-bolt in relation to said first and second clamp assemblies, saidwedge, washer and nut cooperating to allow said T-bolt to secure saidguide bar to said clamp assemblies when said wedge is moved in apredetermined direction.
 16. A guide device for a machining tooloperating upon a workpiece comprising: a guide bar extending beyondcorresponding edges of a preselected portion of the workpiece; means forsecuring said guide bar to the workpiece; means for positioning saidguide bar upon the workpiece to direct the machine tool along apredetermined excursion; means for continuously engaging the machinetool with said guide bar beyond the corresponding edges of thepreselected portion of the workpiece; and means for holding at least twoseparated portions of the workpiece during operation of the machinetool.
 17. A device for routing a machine tool upon a workpiececomprising: a guide bar; means for securing said guide bar to theworkpiece; means for calibrating the position of the guide bar upon theworkpiece; means for enabling the machine tool to separate the workpieceinto at least two distinct portions; and means for securing the relativepositions of the two distinct portions.
 18. The device of claim 17wherein said guide bar includes means for securing the machine tool tosaid guide bar to maintain a predetermined engagement route of themachine tool upon the workpiece.
 19. The device of claim 18 wherein saidsecuring further includes a lateral guide having a first portionremovably positioned upon said guide bar, and a second portion removablyjoined to a receptacle portion of the severing tool.
 20. The device ofclaim 17 wherein said guide bar securing means further includes firstand second clamp assemblies removably joined to preselected portions ofthe workpiece corresponding to a predetermined engagement route of themachine tool upon the workpiece.